1. Field of the Invention
The present invention relates to a capacitor component and a capacitor component mounting structure including a plurality of capacitors that include inner electrodes and dielectric layers alternately laminated.
2. Description of the Related Art
A chip component, particularly a laminated ceramic capacitor, is often used in a mobile terminal device such as a cellular phone and an electronic apparatus such as a personal computer. The laminated ceramic capacitor is configured to include a substantially rectangular component body having inner electrodes and dielectric ceramics alternately laminated and outer electrodes formed on mutually facing opposite ends of the component body.
The outer electrodes are directly mounted on mounting lands of a circuit substrate of an electronic apparatus, and the mounting lands and the outer electrodes are bonded together by a bonding material such as solder. Thereby, the laminated ceramic capacitor is electrically and physically connected to the circuit substrate.
When an alternating-current voltage or a direct-current voltage superimposed with an alternating-current component is applied to such a laminated ceramic capacitor, vibration due to a mechanical strain is generated in the laminated ceramic capacitor by the piezoelectric effect and the electrostrictive effect of the dielectric ceramics. The vibration of the laminated ceramic capacitor is transmitted to the circuit substrate, and the circuit substrate vibrates. Specifically, stress in the normal direction of a mounting surface of the circuit substrate is generated in the circuit substrate by the vibration of the laminated ceramic capacitor, and the circuit substrate vibrates in the normal direction. The vibration of the circuit substrate may produce vibration sound (hereinafter referred to as acoustic noise) audible to the human ear.
As a configuration addressing this issue, Japanese Unexamined Patent Application Publication No. 8-55752, for example, describes a laminated ceramic capacitor mounted on a substrate such that the planes of inner electrodes are oriented substantially perpendicular to a mounting surface of the substrate.
The present inventors, however, have discovered that the acoustic noise of the laminated ceramic capacitor is increased in some cases even in the configuration according to the aforementioned patent application publication, if a plurality of laminated ceramic capacitors are disposed in proximity to one another. With an increase in mounting density due to a reduction in device size, there are not a few cases in which laminated ceramic capacitors are disposed in proximity to one another, and such an issue is not well addressed by the configuration described in the aforementioned patent application publication.